MINNEAPOLIS – Minneapolis police were investigating a shooting inside a downtown nightclub that injured 9 people early Saturday, including a Minnesota Vikings defensive tackle.

Linval Joseph went to the 400 SoundBar nightclub sometime after Minnesota's 10-6 win over the Oakland Raiders in the preseason opener Friday night at TCF Bank Stadium. He was shot in the calf, according to a team statement, which also described him as an innocent bystander and the injury as minor.

Two people with serious injuries were in stable condition Saturday and expected to survive, police spokesman Scott Seroka said. He didn't know the exact condition of the other seven but described most as having minor injuries.

Police are still looking for the shooter. Seroka expected more information to be released Monday.

Club owner Johann Sfaellos told the Star Tribune it was a typical night with patrons busy socializing and dancing, with no fights until he heard gunshots.

"Suddenly, a person just pop, pop, pop," he said of the shooter, who he said dropped the gun on the ground and disappeared before security officers found the gun. "The whole thing was surreal. It was out of the blue."

The Vikings said their thoughts were with the victims and that they were "extremely thankful" that Joseph was not seriously hurt. Joseph is expected to rejoin his coaches and teammates at training camp that will resume Sunday, the team said. Joseph likely won't be able to practice for several days. Vikings players had Saturday off.

Joseph is a nose tackle who signed a five-year contract with the Vikings worth as much as $31.5 million, with $12.5 million guaranteed. He's being counted on as a key cog in new coach Mike Zimmer's defense.

Joseph spent his first four NFL seasons with the New York Giants, starting 46 of 48 games and averaging 55 tackles and three sacks over the last three years. He was also part of the 2011 Super Bowl championship team.